Clinical and genetic associations of autoantibodies to 3‐hydroxy‐3‐methyl‐glutaryl‐coenzyme a reductase in patients with immune‐mediated myositis and necrotizing myopathy

: Inhibition of 3‐hydroxy‐3‐methyl‐glutaryl‐coenzyme A reductase (HMGCR) with statins may trigger idiopathic inflammatory myositis (IIM) or immune‐mediated necrotizing myopathy (IMNM). Anti‐HMGCR antibodies have been detected in patients with IIM/IMNM. We aimed to determine the associations of anti‐HMGCR in IIM/IMNM. Methods : Anti‐HMGCR antibodies were detected by ELISA in sera from patients with IIM/IMNM. Results : Anti‐HMGCR antibodies were detected in 19 of 207 patients with IIM/IMNM, and there was a trend toward an association with male gender ( P  = 0.079). Anti‐HMGCR antibodies were associated strongly with statin exposure (OR = 39, P  = 0.0001) and HLA‐DRB1*11 (OR = 50, P  < 0.0001). The highest risk for development of anti‐HMGCR antibodies was among HLA‐DR11 carriers exposed to statins. Univariate analysis showed a strong association of anti‐HMGCR antibodies with diabetes mellitus ( P  = 0.008), which was not confirmed by multiple regression. Among anti‐HMGCR + patients there was a trend toward increased malignancy ( P  = 0.15). Conclusions : Anti‐HMGCR antibodies are seen in all subtypes of IIM and IMNM and are associated strongly with statin use and HLA‐DR11. Muscle Nerve 52 : 196–203, 2015